Oil-in-water emulsions having a high oil content are used as a cream preparation in the field of medicines and cosmetics or as a mayonnaise-like food in the field of foods. While those having a high oil content of 90% or more are generally difficult to prepare due to difficulty in emulsification and dispersion, it is known that polyoxyethylene surface active agents, which are regarded to have high emulsifying power amongst nonionic surface active agents, are capable of easily emulsifying and dispersing an oily component even in a proportion exceeding 90% (see H. Kunieda et al., Colloids and Surfaces, Vol. 47, p. 35 (1990) and Sagitani, et al., Yukagaku, Vol. 35, p. 102 (1986)).
However, polyoxyethylene surface active agents are known to have a high monomeric solubility in an oily component. Therefore, the surface active agent should be used in an amount of at least 20% by weight based on the total weight of the active agent and an aqueous component in order to obtain a stable oil-in-water emulsion having an oil content as high as 90% by weight or more. Further, since a polyoxyethylene emulsifier undergoes decomposition with the passage of time to produce formalin, this raises a safety problem, making it impossible to apply the resulting emulsion to foods, etc. In addition, when applied to creams or the like, there is another problem in that the emulsion is highly irritative to the skin.